PSYA02H3 Chapter Notes - Chapter 13: Autonomic Nervous System, Egg Cell, Reinforcement

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29 Nov 2012
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CHAPTER 13: Motivation and Emotion
- Human behav is inconsistent; aspects of motivation
motivation is a driving force that moves us to a partic action
motivation: a general term for a group of phenomena that affect the nature, strength, and
persistence of an individual’s behav
→ related to reinforcement
→ behav is motivated by situations; also provoke emotions
1. What is Motivation?
- Usually spoken in terms of goals
→ we behave in a partic way to get something or to avoid something
- Motivation is proactive or forward-looking
→ also reactive; responds to conditions present at the time
- Motivated to perform a behav to gan (or avoid losing) a reinforcer or to avoid (or escape from) an
aversive event
BIOLOGICAL NEEDS
- Biological needs can be very potent motivators
→ need food, air, water, shelter and various vitamins/minerals in order to survive
complex organisms have physio mechanisms that detect deficits or imbalances w/ these needs
→ try to regulate them to bring it back to normal
regulatory behaviour: a behav that tends to bring physio conditions back to normal, thus restoring
the condition of homeostasis
- Homeostasis: the process by which important physiological characteristics (such as body
temperature and blood pressure) are regulated so that they remain at their optimum level
- Regulatory system has 4 essential features:
1) system variable: (characteristic to be regulated) the variable controlled by a regulatory
mechanism; e.g. temp in a heating system
2) set point: (optimum value of the system variable) the optimum value of the system variable in a
regulatory mechanism; set point for human body temp, recorded orally, is approx 37˚C
3) detector: (monitors the value of the system variable) a mechanism that signals when the system
variable deviates from its set point
4) correctional mechanism: the mechanism that is capable of restoring the system variable to the set
point
→ e.g. thermostat heater ctrlling room temp
→ system variable = air in room
→ detector = thermostat
- Negative feedback: a process whereby the effect produced by an action serves to diminish or
terminate that action
→ regulatory systems characterized by negative feedback loops
- Drive reduction hypothesis: the hypothesis that drive (resulting from physio need or depriv) produces
an unpleasant state that causes an organism to engage in motivated behav; reduction of drive is
assumed to be reinforcing
e.g. being deprived of necessities in life, such as food, will produce an unpleasant state, such as
hunger
→ hunger serves as a drive: a condition, often caused by physiological changes or homeostatic
disequilibrium, that energizes an organism’s behav
- Drive associated w/ sexual behav
person can survive w/o sexual behav, but sex drive is motivating and sexual contact is reinforcing
- Drive reduction hypothesis is in disfavour
1) drive is almost always impossible to measure; cannot be experimentally tested
2) if we examine our own behav, we find many events we exp as reinforcing as also exciting, or drive
increasing
→ the exp we want to repeat (ones we find reinforcing) are those that increase, rather than
decrease, our level of arousal
PHYSIOLOGY OF REINFORCEMENT
- Almost all investigators believe that electrical stim of the brain is reinforcing because it activates the
same system that is activated by natural reinforcers and by drugs ppl commonly abuse
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→ normal funct of system is to strengthen the connections b/w neurons that detect the discriminative
stim and the neurons that prod the operant response
- An essential component of the reinforcement system are neurons that release dopamine as
transmitter substance
→ all reinforcing stim seem to trigger the release of dopamine
OPTIMUM-LEVEL THEORY
- When a person wants peace and quiet, avoidance of exciting stim motivates us
produces negative reinforcement
- Optimum-level hypothesis: the hypothesis that organisms will perform behav that restores the level of
arousal to an optimum level
common explanation for positive and negative reinforment
→ when an individ’s arousal level is too high, less stim is reinforcing
→ when it is too low, more stim is desired
- Berlyne hypothesized 2 forms of exploration related to arousal
1) diversive exploration is a response to understimulation (boredom) that incr the diversity of the stim
the organism tries to come in contact w/
2) specific exploration is a response to overstimulation (usually cuz of a specific need) that leads to
the needed item, thereby decr the organism’s drive level
- Hebb focused on house arousal affects the effectiveness of behav
→ at optimum level, mid-range behav is organized and effective
→ w/i optimum level, incr arousal will produce increasingly effective behav
→ too little arousal, suboptimum range,, leads to disorganized and ineffective behav
- Any kind of activity eventually produces satiety, where something that was once reinforcing
becomes bothersome
→ participating in an exciting behav gradually raises an organism’s arousal above its optimum level
- We cannot measure arousal, thus we cant say what its optimum level is
PERSEVERANCE
- The tendency to continue to perform a behav even when it is not being reinforced
→ highly motivated
- Effects of Intermittent Reinforcement
studies have shown that if intermittent training ensures that a reinforced response occurs only after
a series of unreinforced responses, resistance to extinction is greatly enhanced
→ training w/ same # of unreinforced responses in which the reinforcers do not occur even after a
long series of unreinforced responses, does not prod behav that is nearly as resistant to extinction
→ succeeding after several failures causes the learner to resist the effects of subsequent failure
→ exp failure in the past facilitates our persistence or later performance only if its followed by success
→ extinction studies show another motivational effect: enviro stim that are present during extinction
become aversive
e.g. lab animals acquire responses if they allow them to escape enviro in which extinction is
scheduled; FRUSTRATION
→ if another animal is present when the learner’s responses undergo extinction, the other animal may
be attacked; EXTINCTION-INDUCED AGRESSION; scapegoating
- Overjustification Hypothesis
providing extrinsic rewards for behav that is already maintained by intrinsic rewards may actually
weak the target behav
overjustification hypothesis: superfluous application of extrinsic reqards to intrinsically motivated
behav will undermine intrinsic motivation; loss of intrinsic motivation
after a shift occurs from intrinsic to extrinsic motivation and extrinsic rewards disappear, the person
will lose interest in the activity; behav will weaken when extrinsic rewards are no longer available
when rewards are used to challenge and to benefit the learner, they are effective motivators
- Learned Helplessness
organisms w/ a history where their behav has been ineffective in determining its conseq become
less sensitive to the conseq of their behav
→ they lose motivation cuz they learned that they were powerless to affect their own destinies
learned helplessness: a response to exposure to an inescapable aversive stim, characterized by
reduced ability to learn a solvable avoidance task; thought to play a role in the development of
some psychological disturbances
Overmier and Seligman placed dogs in an apparatus in which unavoidable shocks were given;
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then placed dogs in other apparatuses where they were warned before an electrical shock
→ in second situation, animals could avoid the shock by stepping over a small barrier on other side of
apparatus; dogs who were put in the unavoidable shock didn’t learn to escape the shocks
→ they sat in the corner and just took the shocks like it made no difference what they did; learned to
be helpless
→ related affect w/ appetitive stim: acquisition of a learned response is impaired if animals receive
food regardless of their behav before experimenters make food contingent on the response
→ when ppl have exp where they are powerless to ctrl the events that happen to them, they may
become depress and their motivational level may decrease
→ change in motivation occurs cuz the helplessness training reduces their expectation that
performing a task will bring success
2. Eating
- Regulation and expression of eating is one of the most complex motivated behav; all other
motivations depend on it
→ eating aroused when there is a deficit in the body’s supply of stored nutrients and is satisfied by a
meal that replenishes it
→ regulated by physio need
WHAT STARTS A MEAL?
- Eating deals w/ physio factors
→ begins when we have an empty stomach
→ walls of an empty stomach rubs against each other to produce ‘hunger pangs’
→ ‘the rumble theory’
→ removal of the stomach still prod hunger pangs and feelings of hunger and satiety
- Depletion of body’s store of nutrients is a more likely cause of hunger
- Primary fuels for cells in body are glucose and fatty acids
→ sometimes digest tract is empty
→ there must be a reservoir that stores nutrients to keep the cells of the body nourished while the gut
is empty
1)short-term reservoir: stores carbs; located in cells of muscles and the liver
→ full of animal starch; glycogen: an insoluble carb that can be synthesized from glucose or
converted to it; used to store nutrients
→ when glucose enters bloodstream after a meal, some is used for fuel, some is converted to
glycogen
2)long-term reservoir; stores fats; adipose tissue found beneath skin and in the abdomen
→ adipose consists of cells capable of absorbing nutrients from the blood, converting them to
triglycerides and storing them
→ fat cells expand in order to store triglycerides
→ keep us alive during prolonged fasting
- Once level of glycogen is depleted, fat cells release fatty acids and a carb called glycerol
brain cells metabolize glucose exclusively, but other parts of the body can metabolize fatty acids
→ glycerol is converted to glucose
- Mayer proposed the glucostatic hypothesis of hunger
the hypothesis that hunger is caused by a low level or availability of glucose, a condition that is
monitored by specialized sensory neurons
decrease in blood sugar is detected by receptors on glucose-sensitive neurons in the brain, called
glucostats
→ glucostats activate neural circuits that make a person hungry and stim the correctional mech of
eating
→ hypothesis too simple
- An empty stomach causes a hormone, ghrelin, to be secreted
→ stimulator of eating
→ liver also contains two diff types of nutrient receptors, one that detects the level of glucose and
another that detects the level of fatty acids
→ both activate pathways that project to the brain; then they activate neural circuits that initiate
eating
- If certain receptors to the brain are cut, eating fails to occur
- Brain also has receptors detecting levels of glucose and blocking these receptors induces eating
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